High voltage generating device



April 28, 1970 HIDE MIFUNE ET AL 3,509,388

HIGH VOLTAGE GENERATING DEVICE 4 Sheets-Sheet 1 Filed March 20, 1968 Apri128,197o Hmm 'MWUNE ETAL 3,509,388

HIGH VOLTAGE GENERATING DEVICE Filed March 2o, 1988 4 sheets-shet 2 /70 5 I 2m def .82701 ff 28 Q 2e 26 i mt April 28, 1970 H|DE MIFUN ET AL 3,509,388

HIGH VOLTAGE GENERATING DEVICE Filed March 20, 1968 4 Sheets-Sheet 5 HIDEO MIFUNE ETAL 3,509,388 HIGH `VOLTAGE GENERATING DEVICE Aprilzs, 1970 Filed March 2o, 1968 4 Sheets-Sheet 4 United States Patent O 3,509,388 HIGH VOLTAGE GENERATING DEVICE Hideo Mifune and Akira Ishii, Hirakata-shi, and Hiromoto Takeuchi, Kishiwada-shi, Japan, assignors to Matsushita Electric Industrial Co., Ltd., Osaka, Japan, a corporation of Japan Filed Mar. 20, 1968, Ser. No. 714,676 Claims priority, application Japan, Mar. 25, 1967, 42/25,655; Apr. 27, 1967, 42/36,073; June 13, 1967, 42/51,309; June 15, 1967, 42/51,903 (utility models) Int. Cl. H01v 7/ 02 U.S. Cl. S10-8.7 10 Claims ABSTRACT F THE DISCLOSURE A high voltage generating device which is constituted in such a manner that an axially biasing force and a rotational force are normally applied to the striker and the striker is rotated to respectively predetermined directions when it is displaced against the axial biasing force to be given the energy required for striking hard to piezo element, and when it returns to the normal position after the striking.

piezoelectric unit which is manufactured without any special diiculty and assuredly produces a spark required for the ignition of gas when it is used in a gas igniter.

Generally, the essential component elements required for composing a high voltage generating device utilizing a piezoelectric element, include a striker or a hammer for striking the piezoelectric element, means for causing said striker to accumulate an energy required for said striking, and means for letting said accumulated energy release in a moment to make the striker hit hard the piezo element. Conventional means for causing said striker to accumulate the energy include a coil spring and an operating lever engaged to said striker. In such means, the energy is accumulated in the striker by displacing it, by means of an operating body engaged to it, in such a manner that the coil spring is either compressed or expanded by the displacement of the striker. With such an arrangement, if the operating body could move only in one way, the accumulated energy would not be able to be released. Accordingly, in the conventional means, the operating body is provided with a rod which can be projected from the operating body in a direction orthogonal to the direction of travel of the operating body and through which the operating body is engaged to the striker. Such a structure, with the rod contained in the operating body, results in a more complicated mechanism, a larger operating body and a rather awkward operation.

Further, in the conventionl device, two pieces of piezoelectric (hereafter, abbreviated as piezo) elements are generally uned, being stacked to make one unit and a high voltage lead being attached to the electrode provided between the two piezo elements. Such a piezo unit is fabricated in the following manner. That is; iirst an electrode plate is inserted into the central portion of a cylindrical case, and then a piezo element and a buffer plate is inserted to each side of the electrode. Finally, an end plate 3,509,388 Patented Apr. 28, 1970 and a metal tablet are tted to either end of the case. With such an arrangement, however, the impact given by the striker is mostly absorbed by the case, thus reducing so much energy to be given to the piezo elements. Therefore, the voltage produced by such a unit is usually comparatively low.

Moreover, if such a conventional device is to be used for a cigarette lighter, it is necessary to connect a resistor of about 3() kilo-ohms between the piezo element and the spark gap, in order to prolong the sparking period and thus to ensure ignition.

This invention is intended to solve the above-mentioned problem. According to this invention, the striker is under an axially or longitudinally biasing force and a rotational force around the axis in its normal position, and is rotated to respectively predetermined directions when it is displaced against the longitudinally biasing force to be given the energy required for striking the piezo element, and when it returns to the normal position after striking.

This invention will be described hereunder in connection with embodiments and referring to the attached drawings in which:

FIGS. 1, 2 and 3` show an embodiment of this invention, FIG. 1 being a plan view, FIG. 2 an elevation and FIG. 3 an exploded view of the essential parts;

FIGS. 4, 5, 6 and 7 show another embodiment of this invention, FIG. 4 being a plan view, FIG. 5 an elevation, and FIGS. 6 and 7 being isometric views showing the detail of the essential parts;

FIGS, 8, 9 and 10 show another embodiment of this invention, FIG. 8 being an isometric view, FIG. 9 a plan view and FIG. l() an elevation;

FIGS. 11, 12, 13 and 14 show various embodiments of the piezo units used in this invention; and

FIG. 15 shows a schematic diagram of a gas igniter in which the high voltage generating device of this invention is used.

Now, referring to FIGS. 1 to 3, this embodiment of the invention is designed to have such a mechanism that the striker is rotated in the opposite direction of the initially given rotational force when an energy required for a sutiiciently strong strike is accumulated in it and is returned to the initial rotational position when it has returned to the initial longitudinal position after striking the piezo unit.

In FIGS. 1 to 3, reference numeral 1 indicates the enclosure for securing the piezo unit 2 and for slidably receiving the operating body 3. Numeral 4 indicates hooks for securing the piezo unit 2, which extend from the side plates of the enclosure 1.

Numeral 7 shows a spring which is provided between the piezo unit 2 and the operating body 3 received in the enclosure 1 and which is normally pressing the operating body 3 toward the direction indicated by the arrow mark (a). Numeral 8 indicates a guide shaft whose end is secured to the end portion of the operating body 3; 9 the striker slidably fitted to the guide shaft 8; 10 a spring provided between the striker 9 and the end portion of the operating body 3; 11 a stopper rod which is tightly tted in the hole 12 radially bored in the striker 9 and both ends of which are protruding from the periphery of the striker 9; and 16 a schematic representation of an electric conductor which electrically connects the grounded electrode of the piezo unit (often, the metal enclosure 1) to the spark electrode 6 opposing to the other spark electrode 5 derived from the center portion of the piezo unit 2.

Further, both ends of the stopper rod 11 are protruded outward through the openings 14 provided in both sides of the operating body 3 and having a slant side 13 and fur ther through the L-shaped opening 15 provided in the sides of the enclosure 1. And, the striker 9 is normally urged by the spring 10 in the rotational direction indicated by the arrow (b). Accordingly, the end portions of the stopper rod A11 are positioned in the recesses 15 of the openings 15 in a normal state.

In this embodiment, as the end portions of the stopper rod 11 are caught in the recesses 15 of the openings 15 in a normal state, this determines the normal position of the striker 9. Accordingly, if the operating body 3 is pushed against the force of the spring 7 in the direction opposite to that indicated by the arrow (a), another spring provides between the operating body 3 and the striker 9, also is compressed, thus accumulating energy in it. Further pushing of the operating body 3 in the same direction causes the slant side 13 of the opening 14 on the operating body 3 to push the stopper rod 11 obliquely, thereby causing the rod 11 to turn along the slant side |13, until the stopper rod 11 is released from the recess 15 of the opening on the side of the enclosure 1. Then, the striker 9 shoots with the energy accumulated in the spring 10 in the direction opposite to the arrow (a) to hit hard the piezo unit 2.

Upon being thus hard struck, the piezo unit 2 generates a high voltage to make a spark between the electrodes 5 and 6.

With release of the pushing force imposed on the operating body 3 after the hitting, the operating body 3 returns to the initial position, being pushed by the spring 7 in the direction indicated by the arrow (a). Accordingly, the striker 9 also returns to its initial or normal position and the stopper rod 11 enters into the recess 15' of the opening 15 by the rotational force imparted by the spring 10.

Thus, in the above-described embodiment, the striker 9 is caused to longitudinally move to and back and at the same time to rotate to and back only by pushing and releasing the operating body 3, while striking the piezo unit with a suiciently high energy.

Another embodiment of this invention shown in FIGS. 4 to 7 is roughly the same in operation as the abovedescribed embodiment. In FIGS. 4 to 7, reference numeral 17 indicates the enclosure for receiving the piezo unit 18, the striker 19 and other components, and 20 indicates a guide shaft secured to the end portion of the enclosure 17. Numeral 21 indicates a spring provided between the enclosure 17 and the striker l19 to give the striker 19 a rotational force in the direction of the arrow (c) and a longitudinal force in the direction of the arrow (d) in normal state; 22a and 22b openings which are formed on the respective opposite sides 17a and 17b of the enclosure 17 and have oppositely inclined slant sides 23a and 23b respectively; 24a and 24b stopper rods secured to the striker 19 in the radial direction and projecting through said openings 22a and 22b; and 25a, 25b, 25a` and 25d hooks for securing the piezo unit, which extend from the side plates 17a and 17b of the enclosure 17. Further, 26 indicates a plate spring for pushing the piezo unit 18 toward the end of the enclosure 17; 27a and 27b hooks formed at the center portions of the sides 17a and 17b for stopping said plate spring 26; 28 the operating body which is slidably fitted to the outside of the enclosure 17; and 29 a spring provided between the operating body 28 and the enclosure 17 to push the operating body 28 in the direction of the arrow (e) in the normal state. Numerals 30a and 30b indicate slots cut in the opposite sides 28a and 28b of the operating body 28 in respectively opposite directions; 31 a high voltage lead brought out from the piezo unit 18; 32 one of the spark electrodes attached to the end of said high voltage lead 31; 33 an electrically conductive supporter electrically connected to the enclosure 17; and 34 the other spark electrode attached to the end of said supporter 33.

The striker 19 is fitted to the guide shaft 20 in a manner that it can rotate around the shaft 20 and also slide along the shaft 20. In the normal state, the stopper rods 24a and 24b of the striker 19 are trapped in the slots 30a and 30h in the opposite sides of the operating body 28. Therefore, the stopper rods 24a and 24b serve also t0 prevent the operating body 28 from coming olf.

In the above-described embodiment, it is only required to push the operating body 28 in the direction of the arrow (f) (in FIG. 7) or in the opposite direction of the arrow (e) in order to cause the piezo unit to generate a high voltage. That is, by pushing the operational body 28 in the direction indicated by the arrow (f) against the force of the spring 29, the striker 19 is moved in the drection opposite to the arrow (d) by means of the stopper rods 24a and 24b which are trapped in the slots 30a and 30b of the side plates 28a and 28b, and accordingly, the energy required for the striker to hit the piezo unit intensively is accumulated in the spring 21. When the striker 19 comes to a certain position, the stopper rods 24a and 24b come in contact with the slant edges 23a and 23b of the openings 22a and 22h formed in the side plates 17a and 17b of the enclosure 17, and then slide along said slant edges 23a and 23b, thereby turning the striker 19 in the direction opposite to the arrow (c) against the force of the spring 21.

As a result, the stopper rods 24a and 24b are gradually pushed out from the slots 30a and 30b, until the rods are completely released from the slots, when the striker 19 shoots in the direction of the arrow (d) with the energy accumulated in the spring 21, to hit the piezo unit 18 with an intense impact and thus to generate a high voltage.

With release of the pushing force imposed on the operating body 28, it returns to the initial position by the force of the spring 29, and the stopper rods 24a and 24b are again trapped into the slots 30a and 30b.

As described above, with this embodiment, an intense impact enough to generate a high voltage is given to the piezo unit `18 only by pushing the operating body 28 in the direction opposite to the arrow (e) against the force of the spring 29.

FIGS. 8 to 10 show another embodiment of this invention, in which the operating body is of a rotational type and the striker rotates only when it returns to the initial position after striking the piezo unit.

In FIGS. 8 to 10, reference numeral 35 indicates the enclosure; 36 the piezo unit enclosed in one end of the enclosure 35; 37 a plate spring tted to the metal tablet 38 of the piezo unit 36 for securing the piezo unit 36 in place; 39 the striker put in the enclosure 35 facing the piezo unit 36; 40 a recess formed in one end of the striker 39; and 41 a spring provided between the bottom of said recess 40 and one end of the enclosure 35 to impose on the striker 39 a longitudinal force in the direction of the arrow (g) and a rotational force in the direction of the arrow (h) in the normal state. Numeral 42 indicates a stopper rod radially planted on the striker 39 and projecting through the L-shaped opening 43 formed in the side of the enclosure 35; 44 the operating body rotatably tted to the shaft `46 which is supported by the supporter 45 extending from the enclosure 35; 47 a spring tted to the shaft 46 to impose a rotational force in the direction of the arrow (i) on the operating body 44 in the normal state; and 48 an electrically conductive plate electrically connected to the enclosure 35 and supporting an electrode 50 opposedly to the electrode 49 brought out from the piezo unit 36. The operating lbody 44 is provided with a slantedge 51 in the lower end thereof.

In this embodiment, turning of the operating body 44 in the direction opposite to the arrow (i), forces the stopper rod 42 to move in the direction opposite to the arrow (g), thereby accumulating energy in the spring 41, until the end portion of the operating body 44 is disengaged from the stopper rod 42, when the striker 39 shoots back with the accumulated energy to strike the end block 38 of the piezo unit 36, thus causing the piezo unit 36 to generate a high voltage.

After the strike, the operating body 44 is released to be rotated in the direction of the arrow (i) by the spring 47. On the way back, the slant edge S1 of the operating body 44 pushes the stopper rod 42 downward, that is, slightly turns the striker 39 in the 'direction opposite to the arrow (h) against the force of the spring 41. Thus, the operating body `44 returns to the initial position, and the striker 39 also returns to the normal position.

In the high voltage generating devices as described in connection with FIGS. 1 to 10, it is preferable to use a piezo unit such as will be described hereunder. That is, the piezo units as shown in FIGS. l1 to 14 may be used effectively in the high voltage generating devices of this invention.

The piezo unit shown in FIGS. 1l and 12 has a rmly secured metal tablet and an end plate, and is designed so that the substantial part of the impact imparted by the striker is delivered to the piezo element without being absorbed by the case and other parts.

In FIGS. 11 and 12, reference numeral 101 indicates a cylindrical case of synthetic resin which is provided with setback portions 102 and 102 inside of both end portions thereof; 103 an electrode inserted at the mid portion of the cylindrical case 101; 104 a high voltage lead electrically connected to said electrode 103; 105 and 105 the piezo elements tted in the case 101, one end of each being in contact with the electrode 103; 106 and 106' buffers made of metal plate such as aluminum or copper, which are inserted in the portions 102 and 102 and are normally in contact with the piezo elements 105 and 105 respectively; 107 and 108 the metal tablet and the end plate respectively attached to the buffers 106 and 106'; and 109 and 109 protrusions formed at both ends of the case 101 by the aid of heat. It will be understood that the protrusions 109 and 109' need not to be formed all around the peripheries but may `be made at several spots around the peripheries.

As shown in FIGS. 11 and 12, the above-described structure in which the inwardly protrusions 109 and 109 have been made at the edge of the setback portions 102 and 102' formed at both end portions of the case 101, after the metallic buffers 106 and 106', to which the metal tablet 107 and the end plate 108 are respectively attached, have been inserted in the setback portions 102 and 102', assuredly prevents the lbuffers 106 and 106 along with the metal tablet 107 and the end plate 108 from coming off from the case 101 and allows the buffers 106 and 106 to rock within the setback portions 102 and 102. Therefore, the impact applied to the metal tablet 107 is delivered to the piezo elements 105 and 105 through the buffer 106 while being barely absorbed by the case 101. Accordingly, the high voltage can be generated with high efficiency.

FIG. 13 shows an embodiment of the piezo unit suitable for use in a cigarette lighter, in which a lead including a high resistor is used for the lead 104. FIG. 14 shows another embodiment having a similar etect, in which electroresistive elements 110 and 110' are provided between each of the piezo elements 105 and 105 and the electrode plate 103 inserted in the mid portion of the case 101. With either of the above embodiments, no separate resistor is necessary, the high voltage lead 104 can be directly connected to the electrode 111 of the spark gap, as shown in FIG. 15. In FIG. 15, numeral 112 indicates a gas nozzle and 113 a striking mechanism schematically shown.

As described heretofore in connection with various embodiments, the high voltage generating device of this invention makes it possible to accumulate required energy in the striker by a simple operation and to release the stored energy for a moment, thereby causing the striker to hit the piezo unit hard. Further, the impact applied to the piezo unit is delivered to the piezo element with high eiciency, thus ensuring generating of a very high voltage from the piezo unit. The mechanism according to this invention permits the design of a compact high voltage generating device with such a simple constitution that the striker which is normally biased both in axial and rotational directions is brought into action by a single pushing of the operating body which causes the rotation of the striker for releasing it from the operating body.

What is claimed is:

1. A high voltage generating device comprising an enclosure containing a piezoelectric unit; an operating body capable of moving in relation to said enclosure; a striker which can slide in the direction of the axis of said enclosure and which is provided with at least one stopper rod on the peripheral side, said stopper rod being engaged to a portion of at least either one of said enclosure or said operating body; at least one spring for applying to said striker an axial pushing force and a rotational force in predetermined directions and for accumulating sucient energy for said striker to strike hard said piezoelectric unit; means having at least one slant edge formed on that one of said enclosure or said operating body to which said stropper rod is not engaged and for releasing said engagement of said stropper rod according to the movement of said operating body in relation to said enclosure.

2. A high voltage generating device comprising an enclosure containing a piezoelectric unit; an operating body tted in said enclosure with a spring interposed therebetween and capable of moving in the direction of the axis of said enclosure; a striker which can slide in the direction of the axis within said enclosure; at least one spring for applying to said striker an axial pushing force and a rotational force in predetermined directions; at least one stopper rod for stopping said rotational force, end portion of which is projecting through an opening formed on at least one side of `each of said enclosure and said operating body, one of said openings being in the shape of L and the other of said openings having a slant edge, and said stopping rod being turned so as to be released from said engagement according to the movement of said operating body.

3. A high voltage generating device comprising a piezoelectric unit which includes two piezoelectric elements enclosed in a case made of synthetic resin, an electro-conductive plate interposed between said two piezoelectric elements for taking out the generated high voltage and a high voltage lead connected to said electroconductive plate; a box-like enclosure containing said piezoelectric unit; a box-like operating body tted in said enclosure with a counter-acting spring interposed therebetween and capable of moving in the direction of the axis of said enclosure; a striker fitted to a guide shaft provided within said operating body and capable of sliding in the direction of the axis of said guide shaft; at least one spring for applying to said striker an axially pushing force in the direction opposite to that of said counter-acting spring and a rotational force in a predetermined direction; and at least one stopper rod protruding from the peripheral side of said striker, end portion of which is projecting through an opening formed on at least one side of said operating body and having a slant edge and further through an L-shaped opening formed on at least one side of said enclosure, said pushing force and rotational force applied to said striker being stopped by falling of said stopper rod into the recessed portion of said L-shaped opening, said slant edge of said opening formed on the side of said operating body being positioned in such a direction that said stopper rod is disengaged from said recessed portion of the opening when said operating body is moved against the force of said counter-acting spring.

4. A high voltage generating device as defined in claim 1, wherein said spring for applying to said striker an axial pushing force and a rotational force consists of one spring.

5. A high voltage generating device as defined in claim 1, wherein said enclosure and said operating body are respectively in the shape of a box and are fitted to each other in such a manner that one constitutes a guide for the other.

6. A high voltage generating device comprising a piezoelectric unit and a striker disposed in opposed relation to each other in an enclosure; a spring attached to said striker for applying to said striker an axial pushing force and a rotational force in a predetermined direction; at least one stopper rod protruding from the peripheral side of said striker, said stopper rod projecting through an opening formed on at least one side of said enclosure and having a slant edge, and the end portion of said stopper rod being trapped in a slot formed on an operating body which is tted to said enclosure and capable of moving in the axial direction of said operating body.

7. A high voltage generating device constituted in such manner as that a spring for normally applying to the striker a pushing force and a rotational force in respectively predetermined directions is provided between said striker andthe end of the enclosure; that at least one stopper rod provided on the peripheral side of said striker is projected through an opening formed in at least one side of said enclosure for stopping said rotational force; that end portion of the voperating body which is rotatably attached on said enclosure is engaged to said stopper rod, and that suicient energy to hit hard the piezoelectricvunit is accumulated in said spring by turning said operating body.

8. A high voltage generating device as defined in claim 1, in which said piezoelectric unit comprises a cylindrical case which has a setback portion in the inside at either end portion thereof, a metallic buier plate which is movably tted in said setback portion of the case and is in contact with the piezoelectric element, and a metal tablet and an end plate attached to said buffer plate.

9. A high voltage generating device as defined in claim 1, in which a high voltage lead including a high resistor is used for the lead from said piezoelectric unit.

10. A high voltage generating device as dened in claim 1, in which said piezoelectric unit comprises two piezoelectric elements contained in a cylindrical enclosure and electro-resistive elements provided between each of said piezoelectric elements and an electro-conductive plate provided between said two piezoelectric elements.

References Cited UNITED STATES PATENTS 3,384,786 5/1968 Oyamada 317-81 3,307,053 2/1967 Furth 310--8 3,387,912 `6/ 1968 Goto S10-8.7 3,425,783 2/1969 Goto 310--8.7 3,449,637 6/ 1969 Suzuki S10-8.7

I. D. MILLER, Primary Examiner U.S. C1. X.R. 

